Self-aligned gate endcap (sage) architectures with gate-all-around devices

ABSTRACT

Self-aligned gate endcap (SAGE) architectures with gate-all-around devices, and methods of fabricating self-aligned gate endcap (SAGE) architectures with gate-all-around devices, are described. In an example, an integrated circuit structure includes a semiconductor fin above a substrate and having a length in a first direction. A nanowire is over the semiconductor fin. A gate structure is over the nanowire and the semiconductor fin, the gate structure having a first end opposite a second end in a second direction, orthogonal to the first direction. A pair of gate endcap isolation structures is included, where a first of the pair of gate endcap isolation structures is spaced equally from a first side of the semiconductor fin as a second of the pair of gate endcap isolation structures is spaced from a second side of the semiconductor fin.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/017,966, filed on Jun. 25, 2018, the entire contents of which ishereby incorporated by reference herein.

TECHNICAL FIELD

Embodiments of the disclosure are in the field of semiconductor devicesand processing and, in particular, self-aligned gate endcap (SAGE)architectures with gate-all-around devices, and methods of fabricatingself-aligned gate endcap (SAGE) architectures with gate-all-arounddevices.

BACKGROUND

For the past several decades, the scaling of features in integratedcircuits has been a driving force behind an ever-growing semiconductorindustry. Scaling to smaller and smaller features enables increaseddensities of functional units on the limited real estate ofsemiconductor chips. For example, shrinking transistor size allows forthe incorporation of an increased number of memory or logic devices on achip, lending to the fabrication of products with increased capacity.The drive for ever-more capacity, however, is not without issue. Thenecessity to optimize the performance of each device becomesincreasingly significant.

In the manufacture of integrated circuit devices, multi-gatetransistors, such as tri-gate transistors, have become more prevalent asdevice dimensions continue to scale down. In conventional processes,tri-gate transistors are generally fabricated on either bulk siliconsubstrates or silicon-on-insulator substrates. In some instances, bulksilicon substrates are preferred due to their lower cost and becausethey enable a less complicated tri-gate fabrication process. In anotheraspect, maintaining mobility improvement and short channel control asmicroelectronic device dimensions scale below the 10 nanometer (nm) nodeprovides a challenge in device fabrication. Nanowires used to fabricatedevices provide improved short channel control.

Scaling multi-gate and nanowire transistors has not been withoutconsequence, however. As the dimensions of these fundamental buildingblocks of microelectronic circuitry are reduced and as the sheer numberof fundamental building blocks fabricated in a given region isincreased, the constraints on the lithographic processes used to patternthese building blocks have become overwhelming. In particular, there maybe a trade-off between the smallest dimension of a feature patterned ina semiconductor stack (the critical dimension) and the spacing betweensuch features.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates plan views of adjacent integrated circuit structuresfor a conventional architecture with relatively wide spacing (left-handside) versus adjacent integrated circuit structures for a self-alignedgate endcap (SAGE) architecture with relatively tight spacing(right-hand side), in accordance with an embodiment of the presentdisclosure.

FIG. 2 illustrates a plan view of a conventional layout includingfin-based and/or nanowire-based semiconductor devices accommodatingend-to-end spacing.

FIG. 3 illustrates cross-sectional views taken through nanowires andfins for a conventional architecture (left-hand side) versus aself-aligned gate endcap (SAGE) architecture (right-hand side), inaccordance with an embodiment of the present disclosure.

FIG. 4 illustrates cross-sectional views and corresponding plan views ofintegrated circuit structures fabricated (a) without a SAGE isolationstructure, (b) with a SAGE isolation structure fabricated after a fincut process, and (c) with a SAGE isolation structure fabricated before afin cut process, in accordance with an embodiment of the presentdisclosure.

FIG. 5 illustrate cross-sectional views representing various operationsin a method of fabricating a self-aligned gate endcap (SAGE) structurewith gate-all-around devices, in accordance with an embodiment of thepresent disclosure.

FIG. 6A illustrates a three-dimensional cross-sectional view of ananowire-based semiconductor structure, in accordance with an embodimentof the present disclosure.

FIG. 6B illustrates a cross-sectional source or drain view of thenanowire-based semiconductor structure of FIG. 6A, as taken along thea-a′ axis, in accordance with an embodiment of the present disclosure.

FIG. 6C illustrates a cross-sectional channel view of the nanowire-basedsemiconductor structure of FIG. 6A, as taken along the b-b′ axis, inaccordance with an embodiment of the present disclosure.

FIG. 7A illustrates a cross-sectional source or drain view of anothernanowire-based semiconductor structure, in accordance with an embodimentof the present disclosure.

FIG. 7B illustrates a cross-sectional channel view of the nanowire-basedsemiconductor structure of FIG. 7A, in accordance with an embodiment ofthe present disclosure.

FIG. 8A illustrates a cross-sectional source or drain view of anothernanowire-based semiconductor structure, in accordance with an embodimentof the present disclosure.

FIG. 8B illustrates a cross-sectional channel view of the nanowire-basedsemiconductor structure of FIG. 8A, in accordance with an embodiment ofthe present disclosure.

FIGS. 9A-9E illustrate three-dimensional cross-sectional viewsrepresenting various operations in a method of fabricating a nanowireportion of a fin/nanowire structure, in accordance with an embodiment ofthe present disclosure.

FIG. 10A illustrates a cross-sectional view of a nanowire-basedintegrated circuit structure having self-aligned gate endcap isolation,in accordance with an embodiment of the present disclosure.

FIG. 10B illustrates a plan view taken along the a-a′ axis of thesemiconductor devices of FIG. 10A, in accordance with an embodiment ofthe present disclosure.

FIG. 11 illustrates a computing device in accordance with oneimplementation of an embodiment of the disclosure.

FIG. 12 illustrates an interposer that includes one or more embodimentsof the disclosure.

DESCRIPTION OF THE EMBODIMENTS

Self-aligned gate endcap (SAGE) architectures with gate-all-arounddevices, and methods of fabricating self-aligned gate endcap (SAGE)architectures with gate-all-around devices, are described. In thefollowing description, numerous specific details are set forth, such asspecific integration and material regimes, in order to provide athorough understanding of embodiments of the present disclosure. It willbe apparent to one skilled in the art that embodiments of the presentdisclosure may be practiced without these specific details. In otherinstances, well-known features, such as integrated circuit designlayouts, are not described in detail in order to not unnecessarilyobscure embodiments of the present disclosure. Furthermore, it is to beappreciated that the various embodiments shown in the Figures areillustrative representations and are not necessarily drawn to scale.

Certain terminology may also be used in the following description forthe purpose of reference only, and thus are not intended to be limiting.For example, terms such as “upper”, “lower”, “above”, and “below” referto directions in the drawings to which reference is made. Terms such as“front”, “back”, “rear”, and “side” describe the orientation and/orlocation of portions of the component within a consistent but arbitraryframe of reference which is made clear by reference to the text and theassociated drawings describing the component under discussion. Suchterminology may include the words specifically mentioned above,derivatives thereof, and words of similar import.

Embodiments described herein may be directed to front-end-of-line (FEOL)semiconductor processing and structures. FEOL is the first portion ofintegrated circuit (IC) fabrication where the individual devices (e.g.,transistors, capacitors, resistors, etc.) are patterned in thesemiconductor substrate or layer. FEOL generally covers everything up to(but not including) the deposition of metal interconnect layers.Following the last FEOL operation, the result is typically a wafer withisolated transistors (e.g., without any wires).

Embodiments described herein may be directed to back end of line (BEOL)semiconductor processing and structures. BEOL is the second portion ofIC fabrication where the individual devices (e.g., transistors,capacitors, resistors, etc.) are interconnected with wiring on thewafer, e.g., the metallization layer or layers. BEOL includes contacts,insulating layers (dielectrics), metal levels, and bonding sites forchip-to-package connections. In the BEOL part of the fabrication stagecontacts (pads), interconnect wires, vias and dielectric structures areformed. For modern IC processes, more than 10 metal layers may be addedin the BEOL.

Embodiments described below may be applicable to FEOL processing andstructures, BEOL processing and structures, or both FEOL and BEOLprocessing and structures. In particular, although an exemplaryprocessing scheme may be illustrated using a FEOL processing scenario,such approaches may also be applicable to BEOL processing. Likewise,although an exemplary processing scheme may be illustrated using a BEOLprocessing scenario, such approaches may also be applicable to FEOLprocessing.

One or more embodiments of the present disclosure are directed tosemiconductor structures or devices having one or more gate endcapstructures (e.g., as gate isolation regions) of gate electrodes of thesemiconductor structures or devices. Additionally, methods offabricating gate endcap isolation structures in a self-aligned mannerare also described. In one or more embodiments, self-aligned gate endcapstructures are fabricated with gate-all-around features. Embodimentsdescribed herein may address issues associated with scaling diffusionend-to-end spacing in an ultra-scaled process technology.

Particular embodiments may be directed to CMOS integration of multiplewidth (multi-Wsi) nanowires and nanoribbons in a SAGE architecture. Inan embodiment, NMOS and PMOS nanowires/nanoribbons are integrated withmultiple Wsi in a SAGE architecture based front end process flow. Such aprocess flow may involve integration of nanowires and nanoribbons ofdifferent Wsi to provide robust functionality of next generationtransistors with low power and high performance.

To provide context, state-of-the-art approaches have relied onlithographic scaling of the gate end to end (poly cut) to define aminimum technology gate overlap of diffusion. The minimum technologygate overlap of diffusion is a key component in diffusion end to endspace. An associated gate line (poly cut) process has typically beenlimited by lithography, registration, and etch bias considerations, andultimately sets the minimum diffusion end to end distance. Otherapproaches such as contact over active gate (COAG) architectures haveworked to improve such diffusion spacing capability. However,improvements in this technology arena remain highly sought after.

Advantages of a self-aligned gate endcap (SAGE) architecture overconventional approaches may include the enabling of higher layoutdensity and, in particular, scaling of diffusion to diffusion spacing.As an example, FIG. 1 illustrates plan views of adjacent integratedcircuit structures for a conventional architecture with relatively widespacing (left-hand side) versus adjacent integrated circuit structuresfor a SAGE architecture with relatively tight spacing (right-hand side),in accordance with an embodiment of the present disclosure. FIG. 1illustrates plan views of adjacent integrated circuit structures for aconventional architecture with relatively wide spacing (left-hand side)versus adjacent integrated circuit structures for a self-aligned gateendcap (SAGE) architecture with relatively tight spacing (right-handside), in accordance with an embodiment of the present disclosure.

Referring to the left-hand side of FIG. 1, a layout 100 includes first102 and second 104 integrated circuit structures based on semiconductorfins and/or nanowires 106 and 108, respectively. Each device 102 and 104has a gate electrode 110 or 112, respectively. Additionally, each device102 and 104 has trench contacts (TCNs) 114 or 116, respectively, atsource and drain regions of the fins 106 and 108, respectively. Gatevias 118 and 120, and trench contact vias 119 and 121 are also depicted.

Referring again to the left-hand side of FIG. 1, the gate electrodes 110and 112 have a relatively wide end cap region 122, which is located offof the corresponding fins 106 and 108, respectively. The TCNs 114 and116 each have a relatively large end-to-end spacing 124, which is alsolocated off of the corresponding fins 106 and 108, respectively.

By contrast, referring to the right-hand side of FIG. 1, in anembodiment, a layout 150 includes first 152 and second 154 integratedcircuit structures based on semiconductor fins and/or nanowires 156 and158, respectively. Each device 152 and 154 has a gate electrode 160 or162, respectively. Additionally, each device 152 and 154 has trenchcontacts (TCNs) 164 or 166, respectively, at source and drain regions ofthe fins 156 and 158, respectively. Gate vias 168 and 170, and trenchcontact vias 169 and 171 are also depicted.

Referring again to the right-hand side of FIG. 1, the gate electrodes160 and 162 have a relatively tight end cap region, which is located offof the corresponding fins 156 and 158, respectively. The TCNs 164 and166 each have a relatively tight end-to-end spacing 174, which is alsolocated off of the corresponding fins and/or nanowires 156 and 158,respectively.

To provide further context, scaling of gate endcap and trench contact(TCN) endcap regions are important contributors towards improvingtransistor layout area and density. Gate and TCN endcap regions refer togate and TCN overlap of the diffusion region/fin/nanowire ofsemiconductor devices. As an example, FIG. 2 illustrates a plan view ofa conventional layout 200 including fin-based and/or nanowire-basedsemiconductor devices accommodating end-to-end spacing.

Referring to FIG. 2, first 202 and second 204 semiconductor devices arebased on semiconductor fins and/or nanowires 206 and 208, respectively.Each device 202 and 204 has a gate electrode 210 or 212, respectively.Additionally, each device 202 and 204 has trench contacts (TCNs) 214 or216, respectively, at source and drain regions of the fins and/ornanowires 206 and 208, respectively. The gate electrodes 210 and 212 andthe TCNs 214 and 216 each have an end cap region, which is located offof the corresponding fins and/or nanowires 206 and 208, respectively.

Referring again to FIG. 2, typically, gate and TCN endcap dimensionsmust include an allowance for mask registration error to ensure robusttransistor operation for worst case mask mis-registration, leaving anend-to-end spacing 218. Thus, another important design rule critical toimproving transistor layout density is the spacing between two adjacentendcaps facing each other. However, the parameters of “2*Endcap+End-to-End Spacing” are becoming increasingly difficult to scale usinglithographic patterning to meet the scaling requirements for newtechnologies. In particular, the additional endcap length required toallow for mask registration error also increases gate capacitance valuesdue to longer overlap length between TCN and gate electrodes, therebyincreasing product dynamic energy consumption and degrading performance.Previous solutions have focused on improving registration budget andpatterning or resolution improvements to enable shrinkage of both endcapdimension and endcap-to-endcap spacing.

In accordance with an embodiment of the present disclosure, approachesare described which provide for self-aligned gate endcap and TCN overlapof a semiconductor fin and/or nanowire without any need to allow formask registration. In one such embodiment, a disposable spacer isfabricated on the semiconductor fin sidewalls which determines the gateendcap and the contact overlap dimensions. The spacer defined endcapprocess enables the gate and TCN endcap regions to be self-aligned tothe semiconductor fin and, therefore, does not require extra endcaplength to account for mask mis-registration. Furthermore, approachesdescribed herein do not necessarily require lithographic patterning atpreviously required stages since the gate and TCN endcap/overlapdimensions remain fixed, leading to improvement (i.e., reduction) indevice to device variability in electrical parameters.

In accordance with one or more embodiments of the present disclosure,scaling is achieved through a reduction of gate endcap overlap todiffusion by constructing a SAGE wall. As an example, FIG. 3 illustratescross-sectional views taken through nanowires and fins for aconventional architecture (left-hand side) versus a self-aligned gateendcap (SAGE) architecture (right-hand side), in accordance with anembodiment of the present disclosure.

Referring to the left-hand side of FIG. 3, an integrated circuitstructure 300 includes a substrate 302 having fins 304 protrudingtherefrom by an amount 306 above an isolation structure 308 laterallysurrounding lower portions of the fins 304. Corresponding nanowires 305are over the fins 304. A gate structure may be formed over theintegrated circuit structure 300 to fabricate a device. However, breaksin such a gate structure are accommodated for by increasing the spacingbetween fin 304/nanowire 305 pairs.

By contrast, referring to the right-hand side of FIG. 3, an integratedcircuit structure 350 includes a substrate 352 having fins 354protruding therefrom by an amount 356 above an isolation structure 358laterally surrounding lower portions of the fins 304. Correspondingnanowires 305 are over the fins 304. Isolating SAGE walls 360 (which mayinclude a hardmask thereon, as depicted) are included within theisolation structure 352 and between adjacent fin 354/nanowire 355 pairs.The distance between an isolating SAGE wall 360 and a nearest fin354/nanowire 355 pair defines the gate endcap spacing 362. A gatestructure may be formed over the integrated circuit structure 300,between insolating SAGE walls to fabricate a device. Breaks in such agate structure are imposed by the isolating SAGE walls. Since theisolating SAGE walls 360 are self-aligned, restrictions fromconventional approaches can be minimized to enable more aggressivediffusion to diffusion spacing. Furthermore, since gate structuresinclude breaks at all locations, individual gate structure portions maybe layer connected by local interconnects formed over the isolating SAGEwalls 360. In an embodiment, as depicted, the SAGE walls 360 eachinclude a lower dielectric portion and a dielectric cap on the lowerdielectric portion.

In accordance with one or more embodiments of the present disclosure, aself-aligned gate endcap (SAGE) processing scheme involves the formationof gate/trench contact endcaps self-aligned to fins without requiring anextra length to account for mask mis-registration. Thus, embodiments maybe implemented to enable shrinking of transistor layout area.Embodiments described herein may involve the fabrication of gate endcapisolation structures, which may also be referred to as gate walls,isolation gate walls or self-aligned gate endcap (SAGE) walls.

In an embodiment, a SAGE architecture is implemented by fabricating aSAGE isolation structure after a process of cutting the fins to removefin portions in select locations. In another embodiment, SAGE wallformation is performed prior to the finalization of fin geometries. Forcomparative purposes, FIG. 4 illustrates cross-sectional views andcorresponding plan views of integrated circuit structures fabricated (a)without a SAGE isolation structure, (b) with a SAGE isolation structurefabricated after a fin cut process, and (c) with a SAGE isolationstructure fabricated before a fin cut process, in accordance with anembodiment of the present disclosure.

Referring to part (a) of FIG. 4, an integrated circuit structure 400fabricated without a SAGE isolation structure includes a substratehaving a plurality of fin/nanowire pairs 404 protruding therefrom. Anisolation structure 406 laterally surrounds lower portions of the finsof the fin/nanowire pairs 404. Locations 408 indicate regions where finsor portions of fins have been removed, e.g., by a masking and etchprocess. A process sequence for fabricating integrated circuit structure400 may include (i) providing a silicon substrate, (ii) hardmaskformation and patterning on the silicon substrate, (iii) silicon finpatterning by etching the silicon substrate in the presence of thehardmask, (iv) fin cutting by further mask and etch processing, and (v)shallow trench isolation (STI) fill, polish and recess to form isolationstructure 406.

Referring to part (b) of FIG. 4, an integrated circuit structure 420fabricated by forming a SAGE isolation structure after a fin cutprocess, which is referred to herein as a bi-directional SAGEarchitecture, includes a substrate having a plurality of fin/nanowirepairs 424 protruding therefrom. An isolation structure 426 laterallysurrounds lower portions of the fins of the fin/nanowire pairs 424.Locations 428 indicate regions where fin/nanowire pairs or portions offin/nanowire pairs are removed, e.g., by a masking and etch process. ASAGE wall 430 (which may include a hardmask as indicated by thehorizontal line) is formed in locations 428 and has extension portions432 extending from the SAGE wall 430. A process sequence for fabricatingintegrated circuit structure 420 may include (i) providing a siliconsubstrate, (ii) SAGE stack formation, (iii) fin/nanowire precursorpatterning, (iv) fin/nanowire precursor cutting by further mask and etchprocessing, (v) SAGE endcap/wall fabrication, (vi) shallow trenchisolation (STI) fill, polish and recess to form isolation structure 426,and (vii) release of nanowire(s).

Referring to part (c) of FIG. 4, an integrated circuit structure 440fabricated by forming a SAGE isolation structure prior to a fin cutprocess, which is referred to herein as a unidirectional SAGEarchitecture, includes a substrate having a plurality of fin/nanowirepairs 444 protruding therefrom. An isolation structure 446 laterallysurrounds lower portions of the fins of the fin/nanowire pairs 444.Locations 448 indicate regions where fin/nanowire pairs or portions offin/nanowire pairs are removed or are not formed. A SAGE wall 450 (whichmay include a hardmask as indicated by the horizontal line) is formed ina narrow region of location 428. In contrast, to the SAGE wall 430 ofpart (b) of FIG. 4, the SAGE wall 450 has a same width adjacent non-cutfin/nanowire pair portions as the width adjacent a fin/nanowire pair cutportion. A process sequence for fabricating integrated circuit structure420 may include (i) providing a silicon substrate, (ii) SAGE stackformation, (iii) fin/nanowire precursor patterning, (iv) SAGEendcap/wall fabrication, (v) fin/nanowire precursor cutting by furthermask and etch processing, (vi) shallow trench isolation (STI) fill,polish and recess to form isolation structure 446, and (vii) release ofnanowire(s).

Referring to integrated structure 440, as compared to integrated circuitstructure 420, by relocating the wall formation prior to fin/nanowireprecursor cuts, the SAGE wall can be restricted to running along the findirection only. Referring to the plan view (lower portion) of part (c)of FIG. 4, in accordance with an embodiment of the present disclosure,an integrated circuit structure includes a first semiconductorfin/nanowire pair (fin/nanowire pair 444 to immediate left of 450)having a cut along a length of the first semiconductor fin/nanowirepair. A second semiconductor fin/nanowire pair (fin/nanowire pair 444 toimmediate right of 450) has a cut along a length of the secondsemiconductor fin/nanowire pair. A gate endcap isolation structure 450is between the first semiconductor fin/nanowire pair and the secondsemiconductor fin/nanowire pair. The gate endcap isolation structure 450has a substantially uniform width along the lengths of the first andsecond semiconductor fin/nanowire pairs.

In an exemplary processing scheme, FIG. 5 illustrate cross-sectionalviews representing various operations in a method of fabricating aself-aligned gate endcap (SAGE) structure with gate-all-around devices,in accordance with an embodiment of the present disclosure.

Referring to part (a) of FIG. 5, a starting structure includes ananowire patterning stack 504 above a substrate 502. A lithographicpatterning stack 506 is formed above the nanowire patterning stack 504.The nanowire patterning stack 504 includes alternating silicon germaniumlayers 510 and silicon layers 512. A protective mask 514 is between thenanowire patterning stack 504 and the lithographic patterning stack 506.In one embodiment, the lithographic patterning stack 506 is trilayermask composed of a topographic masking portion 520, an anti-reflectivecoating (ARC) layer 522, and a photoresist layer 524. In a particularsuch embodiment, the topographic masking portion 520 is a carbonhardmask (CHM) layer and the anti-reflective coating layer 522 is asilicon ARC layer.

Referring to part (b) of FIG. 5, the stack of part (a) islithographically patterned and then etched to provide an etchedstructure including a patterned substrate 502 and trenches 530.

Referring to part (c) of FIG. 5, the structure of part (b) has anisolation layer 540 and a SAGE material 542 formed in trenches 530. Thestructure is then planarized to leave patterned topographic maskinglayer 520′ as an exposed upper layer.

Referring to part (d) of FIG. 5, the isolation layer 540 is recessedbelow an upper surface of the patterned substrate 502, e.g., to define aprotruding fin portion and to provide a trench isolation structure 541beneath SAGE walls 542.

Referring to part (e) of FIG. 5, the silicon germanium layers 510 areremoved at least in the channel region to release silicon nanowires 512Aand 512B. Subsequent to the formation of the structure of part (e) ofFIG. 5, a gate stacks may be formed around nanowires 512B or 512A, overprotruding fins of substrate 502, and between SAGE walls 542. In oneembodiment, prior to formation of the gate stacks, the remaining portionof protective mask 514 is removed. In another embodiment, the remainingportion of protective mask 514 is retained as an insulating fin hat asan artifact of the processing scheme.

Referring again to part (e) of FIG. 5, it is to be appreciated that achannel view is depicted, with source or drain regions being locatinginto and out of the page. In an embodiment, the channel region includingnanowires 512B has a width less than the channel region includingnanowires 512A. Thus, in an embodiment, an integrated circuit structureincludes multiple width (multi-Wsi) nanowires. Although structures of512B and 512A may be differentiated as nanowires and nanoribbons,respectively, both such structures are typically referred to herein asnanowires. It is also to be appreciated that reference to or depictionof a fin/nanowire pair throughout may refer to a structure including afin and one or more overlying nanowires (e.g., two overlying nanowiresshown in FIG. 5).

To highlight an exemplary nanowire portion of a fin/nanowire pair wherethe nanowire portion includes three nanowires, FIG. 6A illustrates athree-dimensional cross-sectional view of a nanowire-based semiconductorstructure, in accordance with an embodiment of the present disclosure.FIG. 6B illustrates a cross-sectional source or drain view of thenanowire-based semiconductor structure of FIG. 6A, as taken along thea-a′ axis. FIG. 6C illustrates a cross-sectional channel view of thenanowire-based semiconductor structure of FIG. 6A, as taken along theb-b′ axis.

Referring to FIG. 6A, a semiconductor device 600 includes one or morevertically stacked nanowires (604 set) above a substrate 602. A finbetween the bottommost nanowire and the substrate 602 is not depictedfor the sake of emphasizing the nanowire portion for illustrativepurposes. Embodiments herein are targeted at both single wire devicesand multiple wire devices. As an example, a three nanowire-based deviceshaving nanowires 604A, 604B and 604C is shown for illustrative purposes.For convenience of description, nanowire 604A is used as an examplewhere description is focused on one of the nanowires. It is to beunderstood that where attributes of one nanowire are described,embodiments based on a plurality of nanowires may have the sameattributes for each of the nanowires.

Each of the nanowires 604 includes a channel region 606 in the nanowire.The channel region 606 has a length (L). Referring to FIG. 6C, thechannel region also has a perimeter (Pc) orthogonal to the length (L).Referring to both FIGS. 6A and 6C, a gate electrode stack 608 surroundsthe entire perimeter (Pc) of each of the channel regions 606. The gateelectrode stack 608 includes a gate electrode along with a gatedielectric layer between the channel region 606 and the gate electrode(not shown). The channel region is discrete in that it is completelysurrounded by the gate electrode stack 608 without any interveningmaterial such as underlying substrate material or overlying channelfabrication materials. Accordingly, in embodiments having a plurality ofnanowires 604, the channel region 606 of the nanowires are also discreterelative to one another.

Each of the nanowires 604 also includes source and drain regions 610 and612 in the nanowire on either side of the channel region 606. Referringto FIG. 6B, the source or drain regions 610/612 have a perimeter (Psd)orthogonal to the length (L) of the channel region 606. Referring toboth FIGS. 6A and 6B, a pair of contacts 614 surrounds the entireperimeter (Psd) of each of the source or drain regions 610/612. Thesource or drain regions 610/612 are discrete in that they are completelysurrounded by the contacts 614 without any intervening material such asunderlying substrate material or overlying channel fabricationmaterials. Accordingly, in embodiments having a plurality of nanowires604, the source or drain regions 610/612 of the nanowires are alsodiscrete relative to one another. In another embodiment, the source ordrain regions are replaced with single epitaxial source or drainstructures.

Referring again to FIG. 6A, in an embodiment, the semiconductor device600 further includes a pair of spacers 616. The spacers 616 are betweenthe gate electrode stack 608 and the pair of contacts 614. In anembodiment, although not depicted, the source or drain regions 610/612of the nanowires 604 are uniformly doped around the perimeter (Psd) ofeach of the regions. In one such embodiment (also not shown), a dopinglayer is on and completely surrounding the perimeter of each of thesource or drain regions 610/612, between the source or drain regions610/612 and the contact regions 614. In a specific such embodiment, thedoping layer is a boron doped silicon germanium layer, e.g., for a PMOSdevice. In another specific such embodiment, the doping layer is aphosphorous doped silicon layer, e.g., for an NMOS device.

Substrate 602 may be composed of a material suitable for semiconductordevice fabrication. In one embodiment, substrate 602 includes a lowerbulk substrate composed of a single crystal of a material which mayinclude, but is not limited to, silicon, germanium, silicon-germanium ora III-V compound semiconductor material. An upper insulator layercomposed of a material which may include, but is not limited to, silicondioxide, silicon nitride or silicon oxy-nitride is on the lower bulksubstrate. Thus, the structure 600 may be fabricated from a startingsemiconductor-on-insulator substrate. Alternatively, the structure 600is formed directly from a bulk substrate and local oxidation is used toform electrically insulative portions in place of the above describedupper insulator layer. In another alternative embodiment, the structure600 is formed directly from a bulk substrate and doping is used to formelectrically isolated active regions, such as nanowires, thereon. In onesuch embodiment, the first nanowire (i.e., proximate the substrate) isin the form of an omega-FET type structure.

In an embodiment, the nanowires 604 may be sized as wires or ribbons, asdescribed below, and may have squared-off or rounder corners. In anembodiment, the nanowires 604 are composed of a material such as, butnot limited to, silicon, germanium, or a combination thereof. In onesuch embodiment, the nanowires are single-crystalline. For example, fora silicon nanowire 604, a single-crystalline nanowire may be based froma (100) global orientation, e.g., with a <100>plane in the z-direction.As described below, other orientations may also be considered. In anembodiment, the dimensions of the nanowires 604, from a cross-sectionalperspective, are on the nano-scale. For example, in a specificembodiment, the smallest dimension of the nanowires 604 is less thanapproximately 20 nanometers. In an embodiment, the nanowires 604 arecomposed of a strained material, particularly in the channel regions606.

Referring to FIGS. 6B and 6C, in an embodiment, each of the channelregions 606 has a width (Wc) and a height (Hc), the width (Wc)approximately the same as the height (Hc), and each of the source ordrain regions 610/612 has a width (Wsd) and a height (Hsd), the width(Wsd) approximately the same as the height (Hsd). That is, in bothcases, the channel regions 606 and the source or drain region 610/612are square-like or, if corner-rounded, circle-like in cross-sectionprofile. In one such embodiment, Wc and Wsd are approximately the same,and Hc and Hsd are approximately the same, as reflected in FIGS. 6B and6C.

However, in another aspect, the perimeter of the channel region (Pc) maybe smaller than the perimeter of the source or drain regions 610/612(Psd). For example, in accordance with another embodiment of the presentdisclosure, FIG. 7A illustrates a cross-sectional source or drain viewof another nanowire-based semiconductor structure. FIG. 7B illustrates across-sectional channel view of the nanowire-based semiconductorstructure of FIG. 7A.

Referring to FIGS. 7A and 7B, in an embodiment, each of the channelregions 606 has a width (Wc) and a height (Hc), the width (Wc)approximately the same as the height (Hc). Each of the source or drainregions 610/612 has a width (Wsd) and a height (Hsd), the width (Wsd)approximately the same as the height (Hsd). That is, in both cases, thechannel regions 606 and the source or drain region 610/612 aresquare-like or, if corner-rounded, circle-like in cross-section profile.However, in one such embodiment, Wc is less than Wsd, and Hc is lessthan Hsd, as reflected in FIGS. 7A and 7B. In a specific suchembodiments, the perimeters of the source region 610 and the drainregion 612 are approximately the same. In another embodiment, the sourceor drain regions are replaced with single epitaxial source or drainstructures. Accordingly, the perimeters of each of the source or drainregions 610/612 are greater than the perimeter of the channel regions606. Methods to fabricate such an arrangement are described in detailbelow in association with FIGS. 9A-9E.

In another aspect, width and height of the channel region need not bethe same and likewise, the width and height of the source or drainregions need not be the same. For example, in accordance with anotherembodiment of the present disclosure, FIG. 8A illustrates across-sectional source or drain view of another nanowire-basedsemiconductor structure. FIG. 8B illustrates a cross-sectional channelview of the nanowire-based semiconductor structure of FIG. 8A.

Referring to FIGS. 8A and 8B, in an embodiment, each of the channelregions 606 has a width (Wc) and a height (Hc). The width (Wc) issubstantially greater than the height (Hc). For example, in a specificembodiment, the width Wc is approximately 2-10 times greater than theheight Hc. Furthermore, each of the source or drain regions 610/612 hasa width (Wsd) and a height (Hsd), the width (Wsd) substantially greaterthan the height (Hsd). That is, in both cases, the channel regions 606and the source or drain region 610/612 are rectangular-like or, ifcorner-rounded, oval-like in cross-section profile. Nanowires with suchgeometry may be referred to as nanoribbons. In one such embodiment, Weand Wsd are approximately the same, and He and Hsd are approximately thesame, as reflected in FIGS. 8A and 8B. However, in another embodiment,the perimeter of the source or drain regions 610/612 is greater than theperimeter of the channel region 606. In another embodiment, the sourceor drain regions are replaced with single epitaxial source or drainstructures.

Contact resistance may depend on both interface area and the barrierbetween the metal and semiconductor. In an embodiment, methods toimprove contact resistance by reducing the barrier between the metal andsemiconductor by selecting the most advantageous semiconductororientations for the metal to contact are provided. For example, in oneembodiment, a starting silicon (Si) wafer orientation is usedappropriate for forming a contact all around structure wherein more ofthe metal/silicon contact will be with <110> oriented silicon. As anexemplary embodiment to illustrate the concept, reference is made againto FIG. 8A.

Referring to FIG. 8A, the surface of the source or drain region 610/612oriented with Hsd has a <q> crystal orientation. The surface of thesource or drain region 610/612 oriented with Wsd has a <r> crystalorientation. In an embodiment, each of the nanowires is composed ofsilicon, <q> is a <110>orientation, and <r> is a <100> orientation. Thatis, the perimeter along the width of each of the source and drainregions is composed of exposed <110> silicon surfaces, and the perimeteralong the height of each of the source and drain regions is composed ofexposed <100> silicon surfaces. Thus a greater portion of the source ordrain region 610/612 to contact 614 interface is based on an interactionwith <110> silicon surfaces than with <100> silicon surfaces. In anembodiment, such an orientation is achieved by starting with a basesilicon substrate or layer having global (110) orientation, as opposedto the conventional (100) global orientation.

In an alternative embodiment (not shown), the nanoribbons are orientedvertically. That is, each of the channel regions has a width and aheight, the width substantially less than the height, and each of thesource and drain regions has a width and a height, the widthsubstantially less than the height. In one such embodiment, each of thenanowires is composed of silicon, the perimeter along the width of eachof the source and drain regions is composed of exposed <100> siliconsurfaces, and the perimeter along the height of each of the source anddrain regions is composed of exposed <110> silicon surfaces.

As described above, the channel regions and the source or drain regionsare, in at least several embodiments, made to be discrete. However, notall regions of the nanowire need be, or even can be made to be discrete.For example, a cross-sectional spacer view of a nanowire-basedsemiconductor structure includes nanowires 604A-604C that are notdiscrete at the location under spacers 616. In one embodiment, the stackof nanowires 604A-604C have an intervening semiconductor material therebetween, such as silicon germanium intervening between siliconnanowires, or vice versa, as described below in association with FIG.9B.

In another aspect, methods of fabricating a nanowire portion of afin/nanowire semiconductor device are provided. For example, FIGS. 9A-9Eillustrate three-dimensional cross-sectional views representing variousoperations in a method of fabricating a nanowire portion of afin/nanowire structure, in accordance with an embodiment of the presentdisclosure. It is to be appreciated that, for clarity, SAGE wallprocessing is not depicted in association with FIGS. 9A-9E.

A method of fabricating a nanowire semiconductor device may includeforming a nanowire above a substrate. In a specific example showing theformation of two silicon nanowires, FIG. 9A illustrates a substrate 902(e.g., composed of a bulk substrate silicon substrate 902A with aninsulating silicon dioxide layer 902B there on) having a silicon layer904/silicon germanium layer 906/silicon layer 908 stack thereon. It isto be understood that, in another embodiment, a silicon germaniumlayer/silicon layer/silicon germanium layer stack may be used toultimately form two silicon germanium nanowires.

Referring to FIG. 9B, a portion of the silicon layer 904/silicongermanium layer 906/silicon layer 908 stack as well as a top portion ofthe silicon dioxide layer 902B is patterned into a fin-type structure910, e.g., with a mask and plasma etch process. It is to be appreciatedthat, for illustrative purposes, the etch for FIG. 9B is shown asforming two silicon nanowire precursor portions. Although the etch isshown for ease of illustration as ending within a bottom isolationlayer, more complex stacks are contemplated within the context ofembodiments of the present disclosure. For example, the process may beapplied to a nanowire/fin stack as described in association with FIG. 5.

The method may also include forming a channel region in the nanowire,the channel region having a length and a perimeter orthogonal to thelength. In a specific example showing the formation of three gatestructures over the two silicon nanowires, FIG. 9C illustrates thefin-type structure 910 with three sacrificial gates 912A, 912B, and 912Cthereon. In one such embodiment, the three sacrificial gates 912A, 912B,and 912C are composed of a sacrificial gate oxide layer 914 and asacrificial polysilicon gate layer 916 which are blanket deposited andpatterned with a plasma etch process.

Following patterning to form the three sacrificial gates 912A, 912B, and912C, spacers may be formed on the sidewalls of the three sacrificialgates 912A, 912B, and 912C, doping may be performed (e.g., tip and/orsource and drain type doping), and an interlayer dielectric layer may beformed to cover the three sacrificial gates 912A, 912B, and 912C. Theinterlayer dielectric layer may be polished to expose the threesacrificial gates 912A, 912B, and 912C for a replacement gate, orgate-last, process. Referring to FIG. 9D, the three sacrificial gates912A, 912B, and 912C have been removed, leaving spacers 918 and aportion of the interlayer dielectric layer 920 remaining.

Additionally, referring again to FIG. 9D the portions of the silicongermanium layer 906 and the portion of the insulating silicon dioxidelayer 902B of the fin structure 910 are removed in the regionsoriginally covered by the three sacrificial gates 912A, 912B, and 912C.Discrete portions of the silicon layers 904 and 908 thus remain, asdepicted in FIG. 9D.

The discrete portions of the silicon layers 904 and 908 shown in FIG. 9Dwill, in one embodiment, ultimately become channel regions in ananowire-based device. Thus, at the process stage depicted in FIG. 9D,channel engineering or tuning may be performed. For example, in oneembodiment, the discrete portions of the silicon layers 904 and 908shown in FIG. 9D are thinned using oxidation and etch processes. Such anetch process may be performed at the same time the wires are separatedby etching the silicon germanium layer 906. Accordingly, the initialwires formed from silicon layers 904 and 908 begin thicker and arethinned to a size suitable for a channel region in a nanowire device,independent from the sizing of the source and drain regions of thedevice. Thus, in an embodiment, forming the channel region includesremoving a portion of the nanowire, and the resulting perimeters of thesource and drain regions (described below) are greater than theperimeter of the resulting channel region.

The method may also include forming a gate electrode stack surroundingthe entire perimeter of the channel region. In the specific exampleshowing the formation of three gate structures over the two siliconnanowires, FIG. 9E illustrates the structure following deposition of agate dielectric layer 922 (such as a high-k gate dielectric layer) and agate electrode layer 924 (such as a metal gate electrode layer), andsubsequent polishing, in between the spacers 918. That is, gatestructures are formed in the trenches 921 of FIG. 9D. Additionally, FIG.9E depicts the result of the subsequent removal of the interlayerdielectric layer 920 after formation of the permanent gate stack. Theportions of the silicon germanium layer 906 and the portion of theinsulating silicon dioxide layer 902B of the fin structure 910 are alsoremoved in the regions originally covered by the portion of theinterlayer dielectric layer 920 depicted in FIG. 9D. Discrete portionsof the silicon layers 904 and 908 thus remain, as depicted in FIG. 9E.

The method may also include forming a pair of source and drain regionsin the nanowire, on either side of the channel region, each of thesource and drain regions having a perimeter orthogonal to the length ofthe channel region. Specifically, the discrete portions of the siliconlayers 904 and 908 shown in FIG. 9E will, in one embodiment, ultimatelybecome at least a portion of, if not entirely, the source and drainregions in a nanowire-based device. Thus, at the process stage depictedin FIG. 9E, source and drain region engineering or tuning may beperformed, example of which follow. It is to be understood that similarengineering or tuning may instead be performed earlier in a processflow, e.g., prior to deposition of an inter-layer dielectric layer andformation of permanent gate electrodes.

In an embodiment, forming the pair of source and drain regions includesgrowing (e.g., by epitaxial growth) to expand a portion of the nanowire.The perimeters of the source and drain regions may be fabricated to begreater than the perimeter of the channel region in this way. In onesuch embodiment, the nanowire is composed of silicon, and growing theportion of the nanowire includes forming exposed <111> silicon surfacesalong the entire perimeter of each of the source and drain regions. In aspecific such embodiment, forming the exposed <111> silicon surfacesincludes using a deposition and subsequent selective faceted etchprocess. Thus, <111> oriented surfaces may be fabricated by eitherdepositing epitaxial silicon to directly provide <111> facets or bydepositing silicon and using an orientation dependent silicon etch. Inyet another embodiment, the process begins with a thicker nanowirefollowed by subsequent etching using an orientation dependent siliconetch. In an embodiment, forming the pair of source and drain regionsincludes forming a doping layer on and completely surrounding theperimeter of each of the source and drain regions, e.g., a boron dopedsilicon germanium layer. This layer may facilitate formation of ananowire with a uniformly doped perimeter.

The method may also include forming a pair of contacts, a first of thepair of contacts completely surrounding the perimeter of the sourceregion, and a second of the pair of contacts completely surrounding theperimeter of the drain region. Specifically, contacts are formed in thetrenches 925 of FIG. 9E. The resulting structure may be similar to, orthe same as, the structure 600 of FIG. 6A. In an embodiment, thecontacts are formed from a metallic species. In one such embodiment, themetallic species is formed by conformally depositing a contact metal andthen filling any remaining trench volume. The conformal aspect of thedeposition may be performed by using chemical vapor deposition (CVD),atomic layer deposition (ALD), or metal reflow.

In another aspect, system-on-chip (SoC) process technologies typicallyrequire support of standard logic (e.g., low voltage, thin-oxide) andI/O (e.g., high voltage, thick-oxide) transistors. The distinctionbetween standard logic and high voltage (HVI/O) devices may beaccomplished through a multi-oxide process sequence, where logictransistors receive a thin, high-performance oxide and I/O devicesreceive a thick oxide capable to sustain higher voltages. As processtechnologies scale, the logic devices aggressively scale in dimension,creating fabrication challenges with dual-oxide formation. In accordancewith one or more embodiments of the present disclosure, a highvoltage/dual endcap process is used for fabrication of an ultra-scaledfinfet transistor architecture.

To provide context, as technology nodes scale smaller, there is anincreasing lack of geometrical space in a narrow-endcap logic device toaccommodate a defect-free dual oxide process that may be needed forhigh-voltage transistor fabrication. Current approaches rely upon asingle, unscaled endcap space to accommodate a single logic oxideprocess. However, such a process may be incompatible with highly scaledgeometries supporting a dual-oxide high-voltage SoC technology, sincethe endcap space may be insufficient to accommodate both oxides (gatedielectrics).

In accordance with an embodiment of the present disclosure, scalinglimitation imposed by requirements fill high-voltage gates with both thehigh-voltage oxide and logic oxide are addressed. In particular, aslogic dimensions decrease, the endcap space in high voltage (HV) devicesbecomes insufficiently narrow to fill both oxides. In an embodiment,different endcap spaces between logic transistor and high-voltagetransistor, respectively, are fabricated in a SAGE architecture prior toa fin cut process. The logic transistor endcap is ultra-scaled by usingthe self-aligned endcap architecture, while the high-voltage transistorhas a wider endcap to accommodate a thicker gate dielectric. Bothendcaps are unidirectional endcaps in that they are formed by to fin cutprocessing.

One or more embodiments described herein are directed to, or may bereferred to as, a dual unidirectional endcap process flow forultra-scaled logic endcap. To provide context, in a typical SAGE flow, asingle endcap spacer is deposited to form a self-aligned endcapseparating a fin from a SAGE wall. Embodiments described herein mayinvolve formation of differential sacrificial spacer thickness betweenlogic and HV gates. Subsequently, a self-aligned endcap wall is formed.The differential spacer widths are chosen to be thicker in the highvoltage areas, and the standard thickness is used in the logic areas.The differential spacer widths may enable high-voltage oxide to besuccessfully deposited, without sacrificing density in the logic areas.In an embodiment, the thickness of the differential spacer is dependenton the intended HV oxide thickness.

As an example of completed devices, FIG. 10A illustrates across-sectional view of a nanowire-based integrated circuit structurehaving self-aligned gate endcap isolation, in accordance with anembodiment of the present disclosure. FIG. 10B illustrates a plan viewtaken along the a-a′ axis of the semiconductor devices of FIG. 10A, inaccordance with an embodiment of the present disclosure.

Referring to FIG. 10A, a semiconductor structure 1000 includesnon-planar active regions, e.g., a protruding fin portion 1004 and oneor more vertically overlying nanowires 1007. The protruding fin portions1004 may be included in fin structures which further include a sub-finregion 1005 formed from substrate 1002, and within a trench isolationlayer 1006. In an embodiment, the fin structures are a plurality of finlines that form a grating structure such as a tight pitch gratingstructure. In one such embodiment, the tight pitch is not achievabledirectly through conventional lithography. For example, a pattern basedon conventional lithography may first be formed, but the pitch may behalved by the use of spacer mask patterning, as is known in the art.Even further, the original pitch may be quartered by a second round ofspacer mask patterning. Accordingly, grating-like fin patterns may havelines spaced at a constant pitch and having a constant width. Thepattern may be fabricated by a pitch halving or pitch quartering, orother pitch division, approach. Each of the individual fins 1004depicted may represent corresponding individual fins, or may represent aplurality of fins at a given location.

Gate structures 1008 are over the protruding portions 1004 of thenon-planar active regions and around the one or more correspondingvertically overlying nanowires 1007, as well as over a portion of thetrench isolation layer 1006. As shown, gate structures 1008 include agate electrode 1050 and a gate dielectric layer 1052. In one embodiment,although not shown, gate structures 1008 may also include a dielectriccap layer.

Gate structures 1008 are separated by narrow self-aligned gate endcap(SAGE) isolation structures or walls 1020, 1021A or 1021B. The SAGEwalls 1020 each have a width. In an embodiment, the SAGE wall 1021A hasa width greater than the width of each of the SAGE walls 1020, and theSAGE wall 1021B has a width less than the width of each of the SAGEwalls 1020. SAGE walls of differing width may be associated withdifferent device types, as described in an exemplary embodiment below.Each SAGE wall 1020, 1021A or 1021B may include one or more of a localinterconnect 1054 or a dielectric plug 1099 formed thereon. In anembodiment, each of the SAGE walls 1020, 1021A or 1021B is recessedbelow an uppermost surface 1097 of the trench isolation layer 1006, asis depicted in FIG. 10A.

In an exemplary embodiment, the semiconductor structure 1000 includes afirst plurality of semiconductor fin/nanowire pairs (fin/nanowirepair(s) 1004/1007 of region 1070A) above a substrate 1002 and protrudingthrough an uppermost surface 1097 of a trench isolation layer 1006, anda first gate structure (gate structure 1008 of region 1070A) over thefirst plurality of semiconductor fin/nanowire pairs. A second pluralityof semiconductor fin/nanowire pairs (fin/nanowire pair(s) 1004/1007 ofregion 1070B) is above the substrate 1002 and protrudes through theuppermost surface 1097 of the trench isolation layer 1006, and a secondgate structure (gate structure 1008 of region 1070B) is over the secondplurality of semiconductor fin/nanowire pairs. A gate endcap isolationstructure (left-hand SAGE wall 1020) is between and in contact with thefirst gate structure and the second gate structure. A semiconductorfin/nanowire pair of the first plurality of semiconductor fins closestto the gate endcap isolation structure (from region 1070A) is spacedfarther from the gate endcap isolation structure than a semiconductorfin/nanowire pair of the second plurality of semiconductor fins closestto the gate endcap isolation structure (from region 1070B).

In an embodiment, region 1070A is an I/O region, and region 1070B is alogic region. As depicted, in one such embodiment, a second logic region1070C is adjacent the logic region 1070B, and is electrically connectedto the logic region 1070B by a local interconnect 1054. Another region1070D may be a location where an addition logic or I/O region may beplaced. Embodiments described herein may involve differential spacingfrom a SAGE wall (e.g., a wider spacing from SAGE walls 1021B andleft-hand 1020 in region 1070A), or may involve SAGE walls of differingwidth (e.g., narrower 1021B versus 1020 versus wider 1021A), or bothdifferential spacing from a SAGE wall and SAGE walls of differing width.In an embodiment, I/O regions have a greater spacing between SAGE wallsthan a logic region. In an embodiment, a wider SAGE wall is betweenadjacent logic regions than is between adjacent I/O regions.

A gate contact 1014, and overlying gate contact via 1016 are also seenfrom this perspective, along with an overlying metal interconnect 1060,all of which are in inter-layer dielectric stacks or layers 1070. Alsoseen from the perspective of FIG. 10A, the gate contact 1014 is, in oneembodiment, over the non-planar active regions. As is also depicted inFIG. 10A, an interface 1080 exists between a doping profile ofprotruding fin portions 1004 and sub-fin regions 1005, although otherembodiments do not include such an interface in doping profile betweenthese regions.

Referring to FIGS. 10A and 10B, the gate structures 1008 are shown asover the protruding fin portions 1004 and corresponding nanowires 1007,as isolated by self-aligned gate endcap isolation structures 1020. In anembodiment, the gate structures 1008 form one line of a plurality ofparallel gate lines that form a grating structure such as a tight pitchgrating structure. In one such embodiment, the tight pitch is notachievable directly through conventional lithography. For example, apattern based on conventional lithography may first be formed, but thepitch may be halved by the use of spacer mask patterning, as is known inthe art. Even further, the original pitch may be quartered by a secondround of spacer mask patterning. Accordingly, grating-like gate patternsmay have lines spaced at a constant pitch and having a constant width.The pattern may be fabricated by a pitch halving or pitch quartering, orother pitch division, approach.

Referring again to FIG. 10B, source and drain regions 1004A and 1004B ofthe protruding fin portions 1004 and corresponding nanowire(s) 1007 areshown in this perspective, although it is to be appreciated that theseregions would be overlapped with trench contact structures. In oneembodiment, the source and drain regions 1004A and 1004B are dopedportions of original material of the protruding fin/nanowire portions1004/1007. In another embodiment, the material of the protrudingfin/nanowire portions 1004/1007 is removed and replaced with anothersemiconductor material, e.g., by epitaxial deposition. In either case,the source and drain regions 1004A and 1004B may extend below the heightof trench isolation layer 1006, i.e., into the sub-fin region 1005.

In an embodiment, the semiconductor structure 1000 includes non-planardevices such as, but not limited to, a finFET or a tri-gate device withcorresponding one or more overlying nanowire structures. In such anembodiment, a corresponding semiconducting channel region is composed ofor is formed in a three-dimensional body with one or more discretenanowire channel portions overlying the three-dimensional body. In onesuch embodiment, the gate structures 1008 surround at least a topsurface and a pair of sidewalls of the three-dimensional body, andfurther surrounds each of the one or more discrete nanowire channelportions.

Substrate 1002 may be composed of a semiconductor material that canwithstand a manufacturing process and in which charge can migrate. In anembodiment, substrate 1002 is a bulk substrate composed of a crystallinesilicon, silicon/germanium or germanium layer doped with a chargecarrier, such as but not limited to phosphorus, arsenic, boron or acombination thereof, to form active region 1004. In one embodiment, theconcentration of silicon atoms in bulk substrate 1002 is greater than97%. In another embodiment, bulk substrate 1002 is composed of anepitaxial layer grown atop a distinct crystalline substrate, e.g. asilicon epitaxial layer grown atop a boron-doped bulk siliconmono-crystalline substrate. Bulk substrate 1002 may alternatively becomposed of a group III-V material. In an embodiment, bulk substrate1002 is composed of a III-V material such as, but not limited to,gallium nitride, gallium phosphide, gallium arsenide, indium phosphide,indium antimonide, indium gallium arsenide, aluminum gallium arsenide,indium gallium phosphide, or a combination thereof. In one embodiment,bulk substrate 1002 is composed of a III-V material and thecharge-carrier dopant impurity atoms are ones such as, but not limitedto, carbon, silicon, germanium, oxygen, sulfur, selenium or tellurium.

Trench isolation layer 1006 may be composed of a material suitable toultimately electrically isolate, or contribute to the isolation of,portions of a permanent gate structure from an underlying bulk substrateor isolate active regions formed within an underlying bulk substrate,such as isolating fin active regions. For example, in one embodiment,the trench isolation layer 1006 is composed of a dielectric materialsuch as, but not limited to, silicon dioxide, silicon oxy-nitride,silicon nitride, or carbon-doped silicon nitride.

Self-aligned gate endcap isolation structures 1020, 1021A and 1021B maybe composed of a material or materials suitable to ultimatelyelectrically isolate, or contribute to the isolation of, portions ofpermanent gate structures from one another. Exemplary materials ormaterial combinations include a single material structure such assilicon dioxide, silicon oxy-nitride, silicon nitride, or carbon-dopedsilicon nitride. Other exemplary materials or material combinationsinclude a multi-layer stack having lower portion silicon dioxide,silicon oxy-nitride, silicon nitride, or carbon-doped silicon nitrideand an upper portion higher dielectric constant material such as hafniumoxide.

Gate structures 1008 may be composed of a gate electrode stack whichincludes a gate dielectric layer 1052 and a gate electrode layer 1050.In an embodiment, the gate electrode of the gate electrode stack iscomposed of a metal gate and the gate dielectric layer includes a high-Kmaterial.

In an exemplary embodiment, the gate structure 1008 of region 1070Aincludes a first gate dielectric 1052 conformal with the first pluralityof semiconductor fin/nanowire pairs and laterally adjacent to and incontact with a first side of the gate endcap isolation structure(left-hand 1020). The second gate stack of region 1070B includes asecond gate dielectric 1052 conformal with the second plurality ofsemiconductor fin/nanowire pairs and laterally adjacent to and incontact with a second side of the gate endcap isolation structureopposite the first side of the gate endcap isolation structure. In oneembodiment, the first gate dielectric is thicker than the second gatedielectric, as is depicted in FIG. 10A. In one embodiment, the firstgate dielectric has more dielectric layers (e.g., layers 1052A and1052B) than the second gate dielectric (e.g., only layer 1052). In anembodiment, the gate dielectric of region 1070A is an I/O gatedielectric, and the gate dielectric of region 1070B is a logic gatedielectric.

In an embodiment, the gate dielectric of region 1070B is composed of amaterial such as, but not limited to, hafnium oxide, hafniumoxy-nitride, hafnium silicate, lanthanum oxide, zirconium oxide,zirconium silicate, tantalum oxide, barium strontium titanate, bariumtitanate, strontium titanate, yttrium oxide, aluminum oxide, leadscandium tantalum oxide, lead zinc niobate, or a combination thereof.Furthermore, a portion of gate dielectric layer may include a layer ofnative oxide formed from the top few layers of the substrate 1002. In anembodiment, the gate dielectric layer is composed of a top high-kportion and a lower portion composed of an oxide of a semiconductormaterial. In one embodiment, the gate dielectric layer is composed of atop portion of hafnium oxide and a bottom portion of silicon dioxide orsilicon oxy-nitride. In an embodiment, the top high-k portion consistsof a “U”-shaped structure that includes a bottom portion substantiallyparallel to the surface of the substrate and two sidewall portions thatare substantially perpendicular to the top surface of the substrate. Inan embodiment, the gate dielectric of region 1070A includes a layer ofnon-native silicon oxide in addition to a layer of high-k material. Thelayer of non-native silicon oxide may be formed using a CVD process andmay be formed below or above the layer of high-k material. In anexemplary embodiment, the layer of non-native silicon oxide (e.g., layer1052A) is formed below a layer of high-k material (e.g., layer 1052B).

In one embodiment, the gate electrode is composed of a metal layer suchas, but not limited to, metal nitrides, metal carbides, metal silicides,metal aluminides, hafnium, zirconium, titanium, tantalum, aluminum,ruthenium, palladium, platinum, cobalt, nickel or conductive metaloxides. In a specific embodiment, the gate electrode is composed of anon-workfunction-setting fill material formed above a metalworkfunction-setting layer. In some implementations, the gate electrodemay consist of a “U”-shaped structure that includes a bottom portionsubstantially parallel to the surface of the substrate and two sidewallportions that are substantially perpendicular to the top surface of thesubstrate. In another implementation, at least one of the metal layersthat form the gate electrode may simply be a planar layer that issubstantially parallel to the top surface of the substrate and does notinclude sidewall portions substantially perpendicular to the top surfaceof the substrate. In further implementations of the disclosure, the gateelectrode may consist of a combination of U-shaped structures andplanar, non-U-shaped structures. For example, the gate electrode mayconsist of one or more U-shaped metal layers formed atop one or moreplanar, non-U-shaped layers.

Spacers associated with the gate electrode stacks may be composed of amaterial suitable to ultimately electrically isolate, or contribute tothe isolation of, a permanent gate structure from adjacent conductivecontacts, such as self-aligned contacts. For example, in one embodiment,the spacers are composed of a dielectric material such as, but notlimited to, silicon dioxide, silicon oxy-nitride, silicon nitride, orcarbon-doped silicon nitride.

Local interconnect 1054, gate contact 1014, overlying gate contact via1016, and overlying metal interconnect 1060 may be composed of aconductive material. In an embodiment, one or more of the contacts orvias are composed of a metal species. The metal species may be a puremetal, such as tungsten, nickel, or cobalt, or may be an alloy such as ametal-metal alloy or a metal-semiconductor alloy (e.g., such as asilicide material). A common example is the use of copper structuresthat may or may not include barrier layers (such as Ta or TaN layers)between the copper and surrounding ILD material. As used herein, theterm metal includes alloys, stacks, and other combinations of multiplemetals. For example, the metal interconnect lines may include barrierlayers, stacks of different metals or alloys, etc.

In an embodiment (although not shown), providing structure 1000 involvesformation of a contact pattern which is essentially perfectly aligned toan existing gate pattern while eliminating the use of a lithographicstep with exceedingly tight registration budget. In one such embodiment,this approach enables the use of intrinsically highly selective wetetching (e.g., versus conventionally implemented dry or plasma etching)to generate contact openings. In an embodiment, a contact pattern isformed by utilizing an existing gate pattern in combination with acontact plug lithography operation. In one such embodiment, the approachenables elimination of the need for an otherwise critical lithographyoperation to generate a contact pattern, as used in conventionalapproaches. In an embodiment, a trench contact grid is not separatelypatterned, but is rather formed between poly (gate) lines. For example,in one such embodiment, a trench contact grid is formed subsequent togate grating patterning but prior to gate grating cuts.

Furthermore, the gate structures 1008 may be fabricated by a replacementgate process. In such a scheme, dummy gate material such as polysiliconor silicon nitride pillar material, may be removed and replaced withpermanent gate electrode material. In one such embodiment, a permanentgate dielectric layer is also formed in this process, as opposed tobeing carried through from earlier processing. In an embodiment, dummygates are removed by a dry etch or wet etch process. In one embodiment,dummy gates are composed of polycrystalline silicon or amorphous siliconand are removed with a dry etch process including use of SF6. In anotherembodiment, dummy gates are composed of polycrystalline silicon oramorphous silicon and are removed with a wet etch process including useof aqueous NH₄OH or tetramethylammonium hydroxide. In one embodiment,dummy gates are composed of silicon nitride and are removed with a wetetch including aqueous phosphoric acid.

In an embodiment, one or more approaches described herein contemplateessentially a dummy and replacement gate process in combination with adummy and replacement contact process to arrive at structure 1000. Inone such embodiment, the replacement contact process is performed afterthe replacement gate process to allow high temperature anneal of atleast a portion of the permanent gate stack. For example, in a specificsuch embodiment, an anneal of at least a portion of the permanent gatestructures, e.g., after a gate dielectric layer is formed, is performedat a temperature greater than approximately 600 degrees Celsius. Theanneal is performed prior to formation of the permanent contacts.

Referring again to FIG. 10A, in an embodiment, as depicted, asemiconductor device has contact structures that contact portions of agate electrode formed over an active region. In general, prior to (e.g.,in addition to) forming a gate contact structure (such as a via) over anactive portion of a gate and in a same layer as a trench contact via,one or more embodiments of the present disclosure include first using agate aligned trench contact process. Such a process may be implementedto form trench contact structures for semiconductor structurefabrication, e.g., for integrated circuit fabrication. In an embodiment,a trench contact pattern is formed as aligned to an existing gatepattern. By contrast, conventional approaches typically involve anadditional lithography process with tight registration of a lithographiccontact pattern to an existing gate pattern in combination withselective contact etches. For example, a conventional process mayinclude patterning of a poly (gate) grid with separate patterning ofcontact features.

It is to be appreciated that, as exemplified in FIGS. 10A and 10B, SAGEwalls of varying width may be fabricated. It is also to be appreciatedthat fabrication of gate endcap isolation structures may lead toformation of a vertical seam within the gate endcap isolationstructures. It is also to be appreciated that a stack of dielectriclayers may be used to form a SAGE wall. It is also to be appreciatedthat gate endcap isolation structures may differ in compositiondepending on the spacing of adjacent fins.

In an embodiment, as used throughout the present description, interlayerdielectric (ILD) material is composed of or includes a layer of adielectric or insulating material. Examples of suitable dielectricmaterials include, but are not limited to, oxides of silicon (e.g.,silicon dioxide (SiO₂)), doped oxides of silicon, fluorinated oxides ofsilicon, carbon doped oxides of silicon, various low-k dielectricmaterials known in the arts, and combinations thereof. The interlayerdielectric material may be formed by conventional techniques, such as,for example, chemical vapor deposition (CVD), physical vapor deposition(PVD), or by other deposition methods.

In an embodiment, as is also used throughout the present description,metal lines or interconnect line material (and via material) is composedof one or more metal or other conductive structures. A common example isthe use of copper lines and structures that may or may not includebarrier layers between the copper and surrounding ILD material. As usedherein, the term metal includes alloys, stacks, and other combinationsof multiple metals. For example, the metal interconnect lines mayinclude barrier layers (e.g., layers including one or more of Ta, TaN,Ti or TiN), stacks of different metals or alloys, etc. Thus, theinterconnect lines may be a single material layer, or may be formed fromseveral layers, including conductive liner layers and fill layers. Anysuitable deposition process, such as electroplating, chemical vapordeposition or physical vapor deposition, may be used to forminterconnect lines. In an embodiment, the interconnect lines arecomposed of a conductive material such as, but not limited to, Cu, Al,Ti, Zr, Hf, V, Ru, Co, Ni, Pd, Pt, W, Ag, Au or alloys thereof. Theinterconnect lines are also sometimes referred to in the art as traces,wires, lines, metal, or simply interconnect.

In an embodiment, as is also used throughout the present description,hardmask materials, capping layers, or plugs are composed of dielectricmaterials different from the interlayer dielectric material. In oneembodiment, different hardmask, capping or plug materials may be used indifferent regions so as to provide different growth or etch selectivityto each other and to the underlying dielectric and metal layers. In someembodiments, a hardmask layer, capping or plug layer includes a layer ofa nitride of silicon (e.g., silicon nitride) or a layer of an oxide ofsilicon, or both, or a combination thereof. Other suitable materials mayinclude carbon-based materials. Other hardmask, capping or plug layersknown in the arts may be used depending upon the particularimplementation. The hardmask, capping or plug layers maybe formed byCVD, PVD, or by other deposition methods.

In an embodiment, as is also used throughout the present description,lithographic operations are performed using 193 nm immersion litho(i193), EUV and/or EBDW lithography, or the like. A positive tone or anegative tone resist may be used. In one embodiment, a lithographic maskis a trilayer mask composed of a topographic masking portion, ananti-reflective coating (ARC) layer, and a photoresist layer. In aparticular such embodiment, the topographic masking portion is a carbonhardmask (CHM) layer and the anti-reflective coating layer is a siliconARC layer.

Embodiments disclosed herein may be used to manufacture a wide varietyof different types of integrated circuits and/or microelectronicdevices. Examples of such integrated circuits include, but are notlimited to, processors, chipset components, graphics processors, digitalsignal processors, micro-controllers, and the like. In otherembodiments, semiconductor memory may be manufactured. Moreover, theintegrated circuits or other microelectronic devices may be used in awide variety of electronic devices known in the arts. For example, incomputer systems (e.g., desktop, laptop, server), cellular phones,personal electronics, etc. The integrated circuits may be coupled with abus and other components in the systems. For example, a processor may becoupled by one or more buses to a memory, a chipset, etc. Each of theprocessor, the memory, and the chipset, may potentially be manufacturedusing the approaches disclosed herein.

FIG. 11 illustrates a computing device 1100 in accordance with oneimplementation of an embodiment of the present disclosure. The computingdevice 1100 houses a board 1102. The board 1102 may include a number ofcomponents, including but not limited to a processor 1104 and at leastone communication chip 1106. The processor 1104 is physically andelectrically coupled to the board 1102. In some implementations the atleast one communication chip 1106 is also physically and electricallycoupled to the board 1102. In further implementations, the communicationchip 1106 is part of the processor 1104.

Depending on its applications, computing device 1100 may include othercomponents that may or may not be physically and electrically coupled tothe board 1102. These other components include, but are not limited to,volatile memory (e.g., DRAM), non-volatile memory (e.g., ROM), flashmemory, a graphics processor, a digital signal processor, a cryptoprocessor, a chipset, an antenna, a display, a touchscreen display, atouchscreen controller, a battery, an audio codec, a video codec, apower amplifier, a global positioning system (GPS) device, a compass, anaccelerometer, a gyroscope, a speaker, a camera, and a mass storagedevice (such as hard disk drive, compact disk (CD), digital versatiledisk (DVD), and so forth).

The communication chip 1106 enables wireless communications for thetransfer of data to and from the computing device 1100. The term“wireless” and its derivatives may be used to describe circuits,devices, systems, methods, techniques, communications channels, etc.,that may communicate data through the use of modulated electromagneticradiation through a non-solid medium. The term does not imply that theassociated devices do not contain any wires, although in someembodiments they might not. The communication chip 1106 may implementany of a number of wireless standards or protocols, including but notlimited to Wi-Fi (IEEE 802.11 family), WiMAX (IEEE 802.16 family), IEEE802.20, long term evolution (LTE), Ev-DO, HSPA+, HSDPA+, HSUPA+, EDGE,GSM, GPRS, CDMA, TDMA, DECT, Bluetooth, derivatives thereof, as well asany other wireless protocols that are designated as 3G, 4G, 5G, andbeyond. The computing device 1100 may include a plurality ofcommunication chips 1106. For instance, a first communication chip 1106may be dedicated to shorter range wireless communications such as Wi-Fiand Bluetooth and a second communication chip 1106 may be dedicated tolonger range wireless communications such as GPS, EDGE, GPRS, CDMA,WiMAX, LTE, Ev-DO, and others.

The processor 1104 of the computing device 1100 includes an integratedcircuit die packaged within the processor 1104. The integrated circuitdie of the processor 1104 may include one or more structures, such asself-aligned gate endcap (SAGE) structures built in accordance withimplementations of embodiments of the present disclosure. The term“processor” may refer to any device or portion of a device thatprocesses electronic data from registers and/or memory to transform thatelectronic data into other electronic data that may be stored inregisters and/or memory.

The communication chip 1106 also includes an integrated circuit diepackaged within the communication chip 1106. The integrated circuit dieof the communication chip 1106 may include one or more structures, suchas self-aligned gate endcap (SAGE) structures built in accordance withimplementations of embodiments of the present disclosure.

In further implementations, another component housed within thecomputing device 1100 may contain an integrated circuit die thatincludes one or structures, such as self-aligned gate endcap (SAGE)structures built in accordance with implementations of embodiments ofthe present disclosure.

In various implementations, the computing device 1100 may be a laptop, anetbook, a notebook, an ultrabook, a smartphone, a tablet, a personaldigital assistant (PDA), an ultra mobile PC, a mobile phone, a desktopcomputer, a server, a printer, a scanner, a monitor, a set-top box, anentertainment control unit, a digital camera, a portable music player,or a digital video recorder. In further implementations, the computingdevice 1100 may be any other electronic device that processes data.

FIG. 12 illustrates an interposer 1200 that includes one or moreembodiments of the present disclosure. The interposer 1200 is anintervening substrate used to bridge a first substrate 1202 to a secondsubstrate 1204. The first substrate 1202 may be, for instance, anintegrated circuit die. The second substrate 1204 may be, for instance,a memory module, a computer motherboard, or another integrated circuitdie. Generally, the purpose of an interposer 1200 is to spread aconnection to a wider pitch or to reroute a connection to a differentconnection. For example, an interposer 1200 may couple an integratedcircuit die to a ball grid array (BGA) 1206 that can subsequently becoupled to the second substrate 1204. In some embodiments, the first andsecond substrates 1202/1204 are attached to opposing sides of theinterposer 1200. In other embodiments, the first and second substrates1202/1204 are attached to the same side of the interposer 1200. And infurther embodiments, three or more substrates are interconnected by wayof the interposer 1200.

The interposer 1200 may be formed of an epoxy resin, afiberglass-reinforced epoxy resin, a ceramic material, or a polymermaterial such as polyimide. In further implementations, the interposermay be formed of alternate rigid or flexible materials that may includethe same materials described above for use in a semiconductor substrate,such as silicon, germanium, and other group III-V and group IVmaterials.

The interposer may include metal interconnects 1208 and vias 1210,including but not limited to through-silicon vias (TSVs) 1212. Theinterposer 1200 may further include embedded devices 1214, includingboth passive and active devices. Such devices include, but are notlimited to, capacitors, decoupling capacitors, resistors, inductors,fuses, diodes, transformers, sensors, and electrostatic discharge (ESD)devices. More complex devices such as radio-frequency (RF) devices,power amplifiers, power management devices, antennas, arrays, sensors,and MEMS devices may also be formed on the interposer 1200. Inaccordance with embodiments of the disclosure, apparatuses or processesdisclosed herein may be used in the fabrication of interposer 1200 or inthe fabrication of components included in the interposer 1200.

Thus, embodiments of the present disclosure include self-aligned gateendcap (SAGE) architectures with gate-all-around devices, and methods offabricating self-aligned gate endcap (SAGE) architectures withgate-all-around devices.

The above description of illustrated implementations of embodiments ofthe disclosure, including what is described in the Abstract, is notintended to be exhaustive or to limit the disclosure to the preciseforms disclosed. While specific implementations of, and examples for,the disclosure are described herein for illustrative purposes, variousequivalent modifications are possible within the scope of thedisclosure, as those skilled in the relevant art will recognize.

These modifications may be made to the disclosure in light of the abovedetailed description. The terms used in the following claims should notbe construed to limit the disclosure to the specific implementationsdisclosed in the specification and the claims. Rather, the scope of thedisclosure is to be determined entirely by the following claims, whichare to be construed in accordance with established doctrines of claiminterpretation.

EXAMPLE EMBODIMENT 1

An integrated circuit structure includes a semiconductor fin above asubstrate and having a length in a first direction. A nanowire is overthe semiconductor fin. A gate structure is over the nanowire and thesemiconductor fin, the gate structure having a first end opposite asecond end in a second direction, orthogonal to the first direction. Apair of gate endcap isolation structures is included, where a first ofthe pair of gate endcap isolation structures is spaced equally from afirst side of the semiconductor fin as a second of the pair of gateendcap isolation structures is spaced from a second side of thesemiconductor fin. The first of the pair of gate endcap isolationstructures is directly adjacent to the first end of the gate structure,and the second of the pair of gate endcap isolation structures isdirectly adjacent to the second end of the gate structure.

EXAMPLE EMBODIMENT 2

The integrated circuit structure of example embodiment 1, furtherincluding source and drain regions adjacent the nanowire and thesemiconductor fin, on either side of the gate structure, and furtherincluding a first trench contact over the source region and a secondtrench contact over the drain region.

EXAMPLE EMBODIMENT 3

The integrated circuit structure of example embodiment 1 or 2, furtherincluding a second semiconductor fin above the substrate and having alength in the first direction, the second semiconductor fin spaced apartfrom the first semiconductor fin, a second nanowire over the secondsemiconductor fin, a second gate structure over the second nanowire andthe second semiconductor fin, the second gate structure having a firstend opposite a second end in the second direction, where the second ofthe pair of gate endcap isolation structures is directly adjacent to thefirst end of the second gate structure. The integrated circuit structurefurther includes a third gate endcap isolation structure directlyadjacent to the second end of the second gate structure, where the thirdgate endcap isolation structure and the second of the pair of gateendcap isolation structures are centered with the second semiconductorfin.

EXAMPLE EMBODIMENT 4

The integrated circuit structure of example embodiment 3, furtherincluding a local interconnect above and electrically coupling the firstand second gate structures.

EXAMPLE EMBODIMENT 5

The integrated circuit structure of example embodiment 3 or 4, whereinthe second nanowire is wider than the nanowire.

EXAMPLE EMBODIMENT 6

The integrated circuit structure of example embodiment 1, 2, 3, 4 or 5,wherein the gate structure includes a high-k gate dielectric layer and ametal gate electrode.

EXAMPLE EMBODIMENT 7

The integrated circuit structure of example embodiment 1, 2, 3, 4, 5 or6, wherein the pair of gate endcap isolation structures includes amaterial selected from the group consisting of silicon oxide, siliconnitride, silicon carbide, and a combination thereof

EXAMPLE EMBODIMENT 8

The integrated circuit structure of example embodiment 1, 2, 3, 4, 5, 6or 7, wherein the pair of gate endcap isolation structure include alower dielectric portion and a dielectric cap on the lower dielectricportion.

EXAMPLE EMBODIMENT 9

The integrated circuit structure of example embodiment 1, 2, 3, 4, 5, 6,7 or 8, wherein at least one of the pair of gate endcap isolationstructures includes a vertical seam centered therein.

EXAMPLE EMBODIMENT 10

An integrated circuit structure includes a first fin having a longestdimension along a first direction. A first nanowire is over the firstfin. A second fin having a longest dimension is along the firstdirection. A second nanowire is over the second fin. A first gatestructure is over the first nanowire and the first fin, the first gatestructure having a longest dimension along a second direction, thesecond direction orthogonal to the first direction. A second gatestructure is over the second nanowire and over the second fin, thesecond gate structure having a longest dimension along the seconddirection, the second gate structure discontinuous with the first gatestructure along the second direction, and the second gate structurehaving an edge facing an edge of the first gate structure along thesecond direction. A gate endcap isolation structure is between and incontact with the edge of the first gate structure and the edge of thesecond gate structure along the second direction, the gate endcapisolation structure having a length along the first direction greaterthan a length of the first gate structure and the second gate structurealong the first direction.

EXAMPLE EMBODIMENT 11

The integrated circuit structure of example embodiment 10, wherein thesecond nanowire is wider than the nanowire.

EXAMPLE EMBODIMENT 12

The integrated circuit structure of example embodiment 10 or 11, whereinthe gate endcap isolation structure include a lower dielectric portionand a dielectric cap on the lower dielectric portion.

EXAMPLE EMBODIMENT 13

The integrated circuit structure of example embodiment 10, 11 or 12,wherein the gate endcap isolation structure includes a vertical seamcentered therein.

EXAMPLE EMBODIMENT 14

The integrated circuit structure of example embodiment 10, 11, 12 or 13,further including a dielectric material laterally adjacent to and incontact with the gate endcap isolation structure, and the dielectricmaterial having a composition different than a composition of the gateendcap isolation structure.

EXAMPLE EMBODIMENT 15

The integrated circuit structure of example embodiment 10, 11, 12, 13 or14, wherein the first gate structure includes a first gate dielectriclayer and a first gate electrode, and wherein the second gate structureincludes a second gate dielectric layer and a second gate electrode.

EXAMPLE EMBODIMENT 16

The integrated circuit structure of example embodiment 15, wherein thegate endcap isolation structure is in contact with the gate dielectriclayer of the first gate structure and with the gate dielectric layer ofthe second gate structure.

EXAMPLE EMBODIMENT 17

The integrated circuit structure of example embodiment 10, 11, 12, 13,14, 15 or 16, wherein the gate endcap isolation structure has a heightgreater than a height of the first gate structure and greater than aheight of the second gate structure.

EXAMPLE EMBODIMENT 18

The integrated circuit structure of example embodiment 17, furtherincluding a local interconnect over a portion of the first gatestructure, over a portion of the gate endcap isolation structure, andover a portion of the second gate structure.

EXAMPLE EMBODIMENT 19

The integrated circuit structure of example embodiment 18, wherein thelocal interconnect electrically couples the first gate structure to thesecond gate structure.

EXAMPLE EMBODIMENT 20

The integrated circuit structure of example embodiment 19, furtherincluding a gate contact on a portion of the local interconnect over thefirst gate structure, but not on a portion of the local interconnectover the second gate structure.

EXAMPLE EMBODIMENT 21

An integrated circuit structure includes a first semiconductor fin andnanowire pair having a cut along a length of the first semiconductor finand nanowire pair, a second semiconductor fin and nanowire pair having acut along a length of the second semiconductor fin and nanowire pair,and a gate endcap isolation structure between the first semiconductorfin and nanowire pair and the second semiconductor fin and nanowirepair. The gate endcap isolation structure has a substantially uniformwidth along the lengths of the first and second semiconductor fin andnanowire pairs.

EXAMPLE EMBODIMENT 22

The integrated circuit structure of example embodiment 21, wherein thegate endcap isolation structure includes a lower dielectric portion anda dielectric cap on the lower dielectric portion.

EXAMPLE EMBODIMENT 23

The integrated circuit structure of example embodiment 21 or 22, whereinthe gate endcap isolation structure includes a vertical seam centeredwithin the gate endcap isolation structure.

What is claimed is:
 1. An integrated circuit structure, comprising: afirst vertical stack of horizontal nanowires; a second vertical stack ofhorizontal nanowires laterally spaced apart from the first verticalstack of horizontal nanowires; and and a gate endcap isolation structurebetween the first vertical stack of horizontal nanowires and the secondvertical stack of horizontal nanowires, the gate endcap isolationstructure laterally spaced apart from the first vertical stack ofhorizontal nanowires and laterally spaced apart from the second verticalstack of horizontal nanowires.
 2. The integrated circuit structure ofclaim 1, wherein each of the nanowires of the first vertical stack ofhorizontal nanowires has a cross-section having a lateral width and avertical height.
 3. The integrated circuit structure of claim 2, whereinthe lateral width is the same as the vertical height.
 4. The integratedcircuit structure of claim 2, wherein the lateral width is greater thanthe vertical height.
 5. The integrated circuit structure of claim 2,wherein each of the nanowires of the second vertical stack of horizontalnanowires has a cross-section having a lateral width, the lateral widthof each of the nanowires of the second vertical stack of horizontalnanowires the same as the lateral width of each of the nanowires of thefirst vertical stack of horizontal nanowires.
 6. The integrated circuitstructure of claim 2, wherein each of the nanowires of the secondvertical stack of horizontal nanowires has a cross-section having alateral width, the lateral width of each of the nanowires of the secondvertical stack of horizontal nanowires greater than the lateral width ofeach of the nanowires of the first vertical stack of horizontalnanowires.
 7. The integrated circuit structure of claim 1, furthercomprising: a first gate stack over the first vertical stack ofhorizontal nanowires; and a second gate stack over the second verticalstack of horizontal nanowires.
 8. The integrated circuit structure ofclaim 7, wherein the gate endcap isolation structure laterally separatesthe first gate structure from the second gate structure, and wherein thegate endcap isolation structure is in contact with the first gatestructure and the second gate structure.
 9. The integrated circuitstructure of claim 7, wherein each of the first gate structure and thesecond gate structure comprises a gate dielectric and a gate electrode,the integrated circuit structure further comprising: a first pair ofsource or drain structures on either side of the first gate structure;and a second pair of source or drain structures on either side of thesecond gate structure.
 10. The integrated circuit structure of claim 1,wherein the first vertical stack of horizontal nanowires is over a firstfin, and the second vertical stack of horizontal nanowires is over asecond fin.
 11. The integrated circuit structure of claim 1, wherein thegate endcap isolation structure comprises a lower dielectric portion anda dielectric cap on the lower dielectric portion.
 12. A computingdevice, comprising: a board; and a component coupled to the board, thecomponent including an integrated circuit structure, comprising: a firstvertical stack of horizontal nanowires; a second vertical stack ofhorizontal nanowires laterally spaced apart from the first verticalstack of horizontal nanowires; and a gate endcap isolation structurebetween the first vertical stack of horizontal nanowires and the secondvertical stack of horizontal nanowires, the gate endcap isolationstructure laterally spaced apart from the first vertical stack ofhorizontal nanowires and laterally spaced apart from the second verticalstack of horizontal nanowires.
 13. The computing device of claim 12,further comprising: a memory coupled to the board.
 14. The computingdevice of claim 12, further comprising: a communication chip coupled tothe board.
 15. The computing device of claim 12, further comprising: acamera coupled to the board.
 16. The computing device of claim 12,further comprising: a GPS coupled to the board.
 17. The computing deviceof claim 12, further comprising: a compass coupled to the board.
 18. Thecomputing device of claim 12, further comprising: a battery coupled tothe board.
 19. The computing device of claim 12, further comprising: aspeaker coupled to the board.
 20. The computing device of claim 12,wherein the component is a packaged integrated circuit die.